Longitudinal evaluation of compressor/nebulizer performance

Abstract

Background: Inhaled medications are the mainstay of treatment for maintenance of lung health in patients with cystic fibrosis (CF). Compressor/nebulizer units are used an average of 100-120 min/d by patients with CF. Each compressor/nebulizer has unique flow/pressure characteristics that affect particle size distribution and drug output rate. Few data are available regarding longitudinal performance of compressor/nebulizers. We hypothesized that their use over a 24-wk period under conditions similar to those of patients with CF would affect their performance.

Methods: Four new units of compressor/reusable nebulizers from 3 brands (Pari Vios/Pari LC Plus, Pulmo-Aide 5650D/Viox, and Inspiration Elite/SideStream Plus) commonly used by patients with CF were tested. Compressor/nebulizers were operated for 1 h twice daily 5 d/wk for 24 wk. Compressor flow/pressure characteristics were measured every 6 wk. Maximal flow was recorded without and with the nebulizer (MF and MF/NEB, respectively). Pressure was recorded at zero flow (MP) and at MF/NEB (P/NEB). Particle size distribution, inhaled mass (IM), and IM in respirable range were evaluated at baseline and every 12 wk.

Results: Vios had statistically significant declines in MP and P/NEB at each measurement compared with baseline (45.8 and 32.6 psi for MP and 16.7 and 14.3 psi for P/NEB at wk 0 and 24, respectively, P < .05), but other compressors did not. MF and MF/NEB were stable over time but significantly varied among brands. Vios had the greatest slope of flow/pressure relationship (Vios > Pulmo-Aide > Inspiration Elite). Two Vios units stopped working at wk 11 and 24, respectively. All compressors maintained baseline IM, IM in respirable range, and aerosol characteristics.

Conclusions: Long-term use of compressor/nebulizers in a regimen similar to that of patients with CF affected their performance. Pari Vios was the most affected brand, with declines in MP and P/NEB and 2 units that stopped working. Measurement of MF and MF/NEB could help identify compressors that are likely to fail.

Keywords: Compressor; aerosol; breathing simulation; cystic fibrosis; flow; nebulizer; particle size; pressure.